Bonding agents for plastisols containing dotp or dinch

ABSTRACT

A bonding composition for adhering PVC to fabric is disclosed. The bonding composition contains isocyanurate and organophosphate at an organophosphate to isocyanurate weight ratio of 4:1 to 10:1.

FIELD OF THE INVENTION

The invention generally relates to compositions for bonding flexible PVCto synthetic fabric and to their use.

BACKGROUND OF THE INVENTION

There are many applications for polyvinyl chloride (PVC) coated fabrics.These include tarpaulins, conveyor belts, geomembranes, marquees,roofing and cladding materials, protective clothing, floor coverings,and many others. Historically, natural fabrics were used in theseapplications, but the natural fabrics have now been substituted, in manyinstances, with synthetic fibers. Compared to natural fibers, syntheticfibers have been found to offer improved strength, toughness, lightness,moisture resistance, resistance to microorganisms, and flexibility.

Synthetic fibers, however, generally have smooth monofilaments. PVCcoatings tend to have poor mechanical adhesion to smooth surfaces. Toimprove adhesion, a specific bonding agent can be added to the PVCcoating solution (often a plastisol) just prior to application. Thebonding agent chemically bonds with the reactive groups of the fabricand allows the PVC coating to adhere to the fabric.

Most bonding agents incorporate isocyanates. A class of isocyanates iscalled isocyanurate.

It is common to incorporate into the bonding composition anortho-phthalate carrier, for instance, dibutyl phthalate, dioctylphthalate, or diisononyl phthalate (DINP). However, even though usingortho-phthalate carriers is common, such use is often undesirable due topublic opinion on the adverse health effect of phthalates.

Recently, there has been a movement away from using ortho-phthalateplasticizers.

Alternatives to ortho-phthalate plasticizers include dioctylterephthalate (DOTP) (also known as diethylhexyl terephthalate (DENT)),1,2-cyclohexane dicarboxylic acid diisononyl ester (DINCH), hydrogenateddioctyl phthalate (DHEH), hydrogenated DOTP (DOCH), citrates, Mesamoll®(alkylsulfonic acid ester with phenol), butyloctyl terephthalate (BOTP),and isononyl benzoate (INB).

However, commercially available bonding agents can show poorcompatibility with ortho-phthalate free plastisols. Poor compatibilitycan result in a very short pot life due to rapidly increasing plastisolviscosity and gelation of the plastisol shortly after adding the bondingagent.

Thus, there is a need for a bonding agent that shows good compatibilitywith ortho-phthalate free PVC plastisols. There is also a need for abonding agent that, in addition to showing good compatibility withortho-phthalate free PVC plastisols, can improve the adherence of thePVC to fabric, especially synthetic fabric.

The present invention addresses these needs as well as others, whichwill become apparent from the following description and the appendedclaims.

SUMMARY OF THE INVENTION

The invention is as set forth in the appended claims.

Briefly, in one aspect, the present invention provides a bondingcomposition for adhering polyvinyl chloride to fabric. The compositioncomprises (a) isocyanurate and (b) organophosphate at an organophosphateto isocyanurate weight ratio of 4:1 to 10:1.

In another aspect, the present invention provides a coating composition.The coating composition comprises:

(a) a plastisol comprising polyvinyl chloride powder dispersed in aplasticizer comprising dioctyl terephthalate or 1,2-cyclohexanedicarboxylic acid diisononyl ester; and

(b) the bonding composition according to the invention.

In yet another aspect, the present invention provides a process forcoating a fabric. The process comprises:

(a) combining the bonding composition according to the invention with aplastisol comprising polyvinyl chloride powder dispersed in aplasticizer comprising dioctyl terephthalate or 1,2-cyclohexanedicarboxylic acid diisononyl ester; and

(b) coating at least one side of a fabric with the mixture from step(a).

The present invention also provides for articles of manufacturecomprising a fabric coated with the coating composition according to theinvention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a bar graph of the peel strength of various PVC formulationsbased on DINP plasticizer from Example 3.

FIG. 2 is a bar graph of the peel strength of various PVC formulationsbased on DOTP plasticizer from Example 4.

DETAILED DESCRIPTION OF THE INVENTION

It has been found, surprisingly, that organophosphates can improve thecompatibility of bonding agents containing isocyanurates with plastisolscontaining non-ortho-phthalate plasticizers.

Thus, in one aspect, the present invention provides a bondingcomposition for adhering polyvinyl chloride to fabric. The compositioncomprises:

(a) isocyanurate; and

(b) organophosphate,

wherein the weight ratio of organophosphate to isocyanurate ranges from4:1 to 10:1.

The isocyanurate preferably comprises aromatic diisocyanate groups, suchas 2,4-diisocyanatotoluene, 2,6-diisocyanatotoluene, or mixturesthereof. In one embodiment, the isocyanurate comprises 2,4-toluenediisocyanate trimer (CAS #26603-7).

Bonding agents containing isocyanurate are commercially available.Alternatively, the isocyanurate may be prepared by methods usingcatalysts known in the art. For example, isocyanurates can be producedby oligomerization, in particular trimerization, from diisocyanates. Thediisocyanates normally used for this purpose include the isomericdiisocyanatotoluenes (TDI), composed mainly of 2,4-diisocyanatotoluene(2,4-TDI) and 2,6-diisocyanatotoluene (2,6-TDI). These can easily beconverted almost completely to isocyanurates. The isocyanurate may alsobe produced exclusively from 2,4-TDI.

The isocyanurate may be prepared by treating the toluene diisocyanate,either alone or in a suitable solvent, with a basic catalyst such as analiphatic tertiary amine, a basic metallic compound such as an alkali oralkaline earth metal oxide, hydroxide carbonate, alcoholate or phenate,an alkali metal salt of an enolizable compound or a metallic salt of aweak organic carboxylic acid. Co-catalysts may be used, such as, forexample, mono-N-substituted carbamic esters in conjunction with basicmetallic compounds. Catalysts containing metallic salts of weak organiccarboxylic acids, optionally in the presence of a mono-N-substitutedcarbamic ester, can considerably reduce polymerization times.

Suitable solvents for preparing the isocyanurate include solvents thatare inert towards isocyanates, and include, for example, esters such asethyl acetate, butyl acetate, amyl acetate, diethyl phthalate, theacetate of the monoethyl ether of ethylene glycol, dimethyl phthalate,and butyl benzoate; ketones such as methyl isobutyl ketone; chloroform;benzene; toluene; xylene; sulfur dioxide; butyrolactone;monochlorobenzene; o-dichlorobenzene; ethers; or mixtures of suchsolvents.

The preparation of isocyanurate may conveniently be carried out bypolymerizing the toluene diisocyanate with a suitable catalyst until thedesired polymer has been obtained; further polymerization may then beprevented, for example, by mechanical removal of insoluble catalysts byfiltration or by the inactivation of soluble catalysts by treatment withthe calculated amount, or a slight excess thereof, of a strong acid,such as anhydrous hydrogen chloride or phosphoric acid. Alternatively,the toluene diisocyanate may be polymerized to a degree such that therequired polymer formation has taken place and then after removal orinactivation of catalyst, residual free toluene diisocyanate may beremoved by such processes as extraction, distillation, or precipitationof the polymer with a solvent in which the monomeric toluenediisocyanate is soluble.

In addition to diisocyanates, other polyisocyanates may be used toprepare the isocyanurate polymer, for example, p-phenylene diisocyanate,m-phenylene diisocyanate, 1-methoxyphenylene-2,4-diisocyanate,3,3-dimethyl-4,4′-diisocyanatodiphenylmethane,diphenylene-4,4′-diisocyanate, 4,4′-diisocyanatodiphenyl ether,naphthylene-1,5-diisocyanate, hexamethylene diisocyanate,diisocyanatodicyclohexylmethane, p-xylylene diisocyanate, m-xylylenediisocyanate, isocyanatobenzyl isocyanates,1,2,3,4,5,6-hexahydrodiphenylene-4,4′-diisocyanate,4,4′-diisocyanato-1,2,3,4,5,6-hexahydrodiphenylmethane,1,2,3,4-tetrahydronaphthylene-1,5-diisocyanate,toluene-2,4,6-triisocyanate, 3-methyl-4,6,4′-triisocyanatodiphenylmethane, 2,4,4′-triisocyanatodiphenyl,2,4,4′-triisocyanato-diphenyl ether, 4,4′-diisocyanatodiphenyl methane,1-chlorophenylene-2,4-diisocyanate, and p-isocyanato benzyl isocyanate.

The amount of isocyanurate in the bonding composition may range from 0.5to 30% by weight, based on the total weight of the bonding composition.Other amounts of the isocyanurate are possible, such as from 5 to 30% byweight, 8 to 30% by weight, 10 to 30% by weight, 0.5 to 25% by weight, 5to 25% by weight, 8 to 25% by weight, 10 to 25% by weight, 0.5 to 20% byweight, 5 to 20% by weight, 8 to 20% by weight, 10 to 20% by weight, 0.5to 15% by weight, 5 to 15% by weight, 8 to 15% by weight, or 10 to 15%by weight.

Any organophosphate that can improve the compatibility of isocyanuratewith PVC plastisols containing non-ortho-phthalate plasticizers can beused in the bonding composition according to the invention. Suchorganophosphates include those containing alkyl or aryl groups having 7to 10 carbon atoms. Specific examples of suitable organophosphatesinclude tri-ethylhexyl phosphate, tricresyl phosphate, isodecyl diphenylphosphate, 2-ethylhexyl diphenyl phosphate, or mixtures thereof. In oneembodiment, the organophosphate comprises tri-ethylhexyl phosphate.

The amount of organophosphate in the bonding composition may range from50 to 99.5% by weight, based on the total weight of the bondingcomposition. Other amounts of the organophosphate are possible, such asfrom 75 to 99.5% by weight, 80 to 99.5% by weight, 85 to 99.5% byweight, 50 to 95% by weight, 75 to 95% by weight, 80 to 95% by weight,85 to 95% by weight, 50 to 92% by weight, 75 to 92% by weight, 80 to 92%by weight, 85 to 92% by weight, 50 to 90% by weight, 75 to 90% byweight, 80 to 90% by weight, or 85 to 90% by weight.

The weight ratio of organophosphate to isocyanurate in the bondingcomposition ranges from 4:1 to 10:1. In one embodiment, the weight ratioof organophosphate to isocyanurate ranges from 4.5:1 to 10:1. In yetother embodiments, the weight ratio of organophosphate to isocyanurateranges from 5:1 to 10:1, 6:1 to 10:1, 7:1 to 10:1, 4:1 to 9:1, 5:1 to9:1, 6:1 to 9:1, or 7:1 to 9:1.

The bonding composition may also include typical amounts of traditionaladditives such as flame retardants, stabilizers, chlorinatedhydrocarbons, secondary plasticizers, viscosity depressants,antioxidants, or mixtures thereof.

The components of the bonding composition according to the invention maybe combined in any known manner, including simultaneously orsequentially. Heating may facilitate dissolution of one or more of thecomponents along with vigorous mixing.

The bonding composition of the invention is particularly suitable asadhesion promoters for plasticized PVC and in particular for PVCplastisols.

Thus, in another aspect, the invention provides a coating composition.The coating composition comprises:

(a) a plastisol comprising polyvinyl chloride (PVC) powder dispersed ina plasticizer comprising dioctyl terephthalate or 1,2-cyclohexanedicarboxylic acid diisononyl ester; and

(b) the bonding composition according to the invention.

The plastisol typically contains from 20 to 150 parts by weight ofplasticizer per 100 parts of PVC powder. In one embodiment, theplastisol contains from 40 to 120 parts by weight of plasticizer per 100parts of PVC powder.

In one embodiment, the plasticizer is dioctyl terephthalate.

In addition to PVC, the plastisol may include vinyl copolymers such asvinyl acetate or vinyl acrylate.

The amount of the bonding composition employed in the coatingcomposition can vary, depending on the desired degree of adhesion andthe isocyanurate content of the bonding composition. For example, for abonding composition containing 25 wt % of isocyanurate, the coatingcomposition typically contains from 1 to 8 wt % of the bondingcomposition. As another example, for a bonding composition containing 8to 20 wt % of isocyanurate, the coating composition may contain from 1to 20% by weight of the bonding composition. In one embodiment, thecoating composition contains from 4 to 20% by weight of the bondingcomposition. In another embodiment, the coating composition containsfrom 4 to 15% by weight of the bonding composition. The amount by weightof the bonding composition is based on the total weight of the coatingcomposition.

The coating composition according to the invention may further comprisea variety of additives, such as flame retardants (e.g., antimonytrioxide or aluminum trihydroxide), stabilizers (including epoxystabilizers), fillers (e.g., calcium carbonate or dolomite), pigments(e.g., titanium dioxide, carbon black, or ultramarine blue), chlorinatedhydrocarbons, plasticizers, viscosity depressants (e.g., white spirit ortallates), antioxidants (e.g., 2,6-di-t-butyl-4-methylphenol,3,5-bis(1,1-dimethylethyl)-4-hydroxybenzenepropanoic acid octadecylester, butylated hydroxytoluene, or octadecyl3,5-di-t-butyl-4-hydroxyhydrocinnamate), UV absorbers (e.g.,2-hydroxyphenylbenzotriazole or 2-hydroxybenzophenones), biocides (e.g.,2-n-octyl-4-isothiazolin-3-one,4,5,-dichloro-2-n-octyl-4-isothiazolin-3-one or10,10′-oxybisphenoxarsine), or mixtures thereof.

The bonding agent is typically added to the plastisol, mixed at slightlyelevated temperature (e.g., 20-30° C.), and de-aerated shortly beforeuse. The mixed composition is particularly suitable for coating fabric,particularly fabric made from synthetic fiber.

Thus, in another aspect, the invention provides a process for coating afabric. The process comprises:

(a) combining the bonding composition according to the invention with aplastisol comprising polyvinyl chloride powder dispersed in aplasticizer comprising dioctyl terephthalate or 1,2-cyclohexanedicarboxylic acid diisononyl ester; and

(b) coating at least one side of a fabric with the mixture from step(a).

The fabric to be coated preferably comprises polyester or polyamidefibers. The fabric may be coated on one or both sides using techniquesknown in the art, such as by spreading, dipping, or calendering onconventional equipment.

In one embodiment, the coating process further comprises (c) exposingthe coated fabric to elevated temperature to fuse the coating. Thefusing step may be carried out, for example, at a temperature of 110 to210° C. for 30 to 90 seconds, until fusion is sufficiently completed.

Additional coats of the coating composition of the invention, or ofanother PVC composition may subsequently be applied and heated in asimilar fashion.

The present invention also provides for articles of manufacturecomprising a fabric coated with the coating composition according to theinvention. Such articles of manufacture include tarpaulins, billboards,air-supported structures and other textile structures, flexiblecontainers, polygonal roofs, geomembranes, pool-liners, awnings,protective apparel, conveyor belts, flock carpets, and foamed syntheticleather.

The present invention includes any and all combinations of embodiments,features, parameters, and/or ranges disclosed herein. That is, theinvention may be defined by any combination of embodiments, features,parameters, and/or ranges described herein.

As used herein, the indefinite articles “a” and “an” mean one or more,unless the context clearly suggests otherwise. Similarly, the singularform of nouns includes their plural form, and vice versa, unless thecontext clearly suggests otherwise.

While attempts have been made to be precise, the numerical values andranges described herein should be considered to be approximations (evenwhen not qualified by the term “about”). These values and ranges mayvary from their stated numbers depending upon the desired propertiessought to be obtained by the present invention as well as the variationsresulting from the standard deviation found in the measuring techniques.Moreover, the ranges described herein are intended and specificallycontemplated to include all sub-ranges and values within the statedranges. For example, a range of 50 to 100 is intended to describe andinclude all values within the range including sub-ranges such as 60 to90 and 70 to 80.

The content of all documents cited herein, including patents as well asnon-patent literature, is hereby incorporated by reference in theirentirety. To the extent that any incorporated subject matter contradictswith any disclosure herein, the disclosure herein shall take precedenceover the incorporated content.

This invention can be further illustrated by the following examples ofpreferred embodiments thereof, although it will be understood that theseexamples are included merely for purposes of illustration and are notintended to limit the scope of the invention.

EXAMPLES

Table 1 shows the commercial bonding agents that were tested in theexamples below, where DINP is diisononyl phthalate, INB is isononylbenzoate, and TEHP is triethylhexyl phosphate.

TABLE 1 Isocyanate Content Bonding Agent Supplier (wt %) CarrierVulcabond MDX Akcros Chemicals 25 DINP Nourybond 289 Air Products 25DINP Nourybond 290 Air Products 30 DINP TL LXS 51099 Lanxess 25 INBPermuthane XR 13 Stahl Waalwijk 25 DINP 553 Vulcabond TP AkcrosChemicals 25 TEHP Vulcabond TP30 Akcros Chemicals 30 TEHP Permuthane XR22- Stahl Waalwijk 30 DINP 556

Table 2 shows the plasticizers that were tested.

TABLE 2 Plasticizer Name Abbreviation diisononyl phthalate DINP dioctylterephthalate DOTP trimethyl pentanyl diisobutyrate TXIB di-butylterephthalate DBT Benzoflex 9-88 B 9-88 Benzoflex 1046 B 1046 TriacetinTriacetin 1,2-cyclohexane dicarboxylic acid diisononyl DINCH esterbis(2-propylheptyl) phthalate DPHP

Example 1

To quickly determine the compatibility of the plasticizers with thecommercial bonding agents and to detect visual changes, the commercialbonding agents were mixed directly with the plasticizers, instead ofusing PVC plastisols.

The mixtures were prepared by adding the plasticizer to the bondingagent in a vial at a 5:1 weight ratio of plasticizer to bonding agent,shaking the vial firmly by hand, and then observing the mixture after 24hours.

The appearance of the mixtures was rated for cloudiness, gelation, colorchange, and viscosity according to scale set forth in Table 3.

TABLE 3 Rating Appearance 5 Clear, colorless, easily pourable 4 Clear,slightly colored, easily pourable 3 Turbid, white, easily pourable 2Some residue, easily pourable 1 Turbid, colored, gelled

The appearance rating of the mixtures is reported in Table 4.

TABLE 4 Plasticizer Bonding Agent DINP DOTP TXIB DBT B 9-88 B 1046Triacetin DINCH DPHP Vulcabond MDX 5 1 n/t n/t n/t n/t n/t 1 5 Nourybond289 5 2 n/t 5 n/t 5 5 5 n/t Nourybond 290 2 2 n/t n/t n/t 4 2 2 n/t TLLXS 51099 5 1 1 1 1 1 1 3 n/t Permuthane 5 2 1 1 1 n/t n/t 4 5 XR 13 553Vulcabond TP 5 3 5 n/t n/t n/t 5 5 5 Vulcabond TP30 5 1 5 5 n/t n/t n/tn/t 5 Permuthane 5 1 1 5 5 5 5 5 5 XR 22-556 n/t = not tested

As seen from Table 4, the results show that DINP and DPHP, bothortho-phthalates, are more compatible with most of the tested bondingagents than the other plasticizers tested. DOTP, in particular, showedlow compatibility with most of the tested bonding agents.

Example 2

The procedure of Example 1 was repeated with mixtures containing 2 partsby weight of bonding agent, 6 parts by weight of DOTP as theplasticizer, and 1 part by weight of triethylhexyl phosphate (TEHP) as acompatibilizer.

The appearance of the mixtures was rated using the scale in Table 3immediately after mixing as well as after 3 days. The results arereported in Table 5.

TABLE 5 Plasticizer DOTP DOTP Bonding Agent Compatibilizer Initial 3Days Vulcabond MDX TEHP 5 2 Nourybond 289 TEHP 5 5 Nourybond 290 TEHP 11 TL LXS 51099 TEHP 3 3 Permuthane XR 13 553 TEHP 5 4 Vulcabond TP TEHP5 5 Vulcabond TP30 TEHP 5 5 Permuthane XR 22-556 TEHP 5 4

As seen from Table 5, adding TEHP significantly improved thecompatibility of DOTP with the bonding agents.

Example 3

A plastisol was prepared by mixing the ingredients shown in Table 6 atthe listed proportions.

TABLE 6 Amount Plastisol Formulation (parts by weight) Plasticizer DINP77 Stabilizer Lankromark E2307 (ESBO) 3 Lankrostab LZB 600 2 PVC GradeLacovyl PB 1702 40 Vestolit B7021 ultra 60 Filler Omyacarb 5 GU 15 Total197

Adhesive compositions were prepared by adding 2, 3, or 4 wt % of thebonding agent Vulcabond TP to the prepared plastisol at 30° C. Thecompositions were properly mixed and de-aerated. Vulcabond TP is a 25 wt% isocyanurate solution mainly in a mixture of DBT (50 wt %) and TEHP(15 wt %).

A second bonding agent was prepared using a mixture of Vulcabond TP andTEHP in a 1:1 weight ratio. The dosing level of this bonding agent wastwice the amount of the neat Vulcabond TP, since the isocyanate contentwas diluted to 12.5 wt % with the TEHP. Adhesive compositions wereprepared by adding 4, 6, and 8 wt % of the second bonding agent to theprepared plastisol at 30° C. The compositions were properly mixed andde-aerated.

The adhesive compositions were then coated onto 12 fiber threads/cm×12fiber threads/cm sheets of polyester fiber (DEWHURST, 550 dtex) at alayer thickness of 100 g/m² and placed in a Werner Mathis oven within 1hour of adding the bonding agent. Additional coated samples wereprepared with adhesive compositions that were allowed to sit for 24hours at 30° C.

The adhesive compositions on the coated fabric were fused in the oven at190° C. for 1 minute.

The coated fabric samples were then subjected to a 90° peel test.

Peel Test Procedure

Two test pieces of coated fabric size 3×20 cm were HF welded togetherwith the coated sides facing each other, for an area of 2×15 cm.

Each loose end of the test sample was clamped in a material test machineand peeled under an angle of 90 degrees at a speed of 100 mm/min. Theaverage peel force was measured on 8 cm of the welded area, disregardingthe start and ending of the test.

The force was extrapolated to N/5 cm bond width.

The peel test results are shown in FIG. 1 along with a coated samplethat was made with just the prepared plastisol and no bonding agent.

As seen from FIG. 1, the results show a good increase in peel strengthwith increasing amount of bonding agent. The Vulcabond TP/TEHP 50/50mixture results were comparable with the neat Vulcabond TP results. Theresults of adhesive compositions that were allowed to sit for 24 hoursat 30° C. showed little increase in peel strength, which is expected dueto the limited pot life of the adhesive composition.

Example 4

Example 3 was repeated except that DINP in the prepared plastisol wasreplaced with DOTP.

The 90° peel test results are shown in FIG. 2 along with a coated samplethat was made with just the prepared plastisol and no bonding agent.

As seen from FIG. 2, the results for DOTP adhesive compositions showedgood peel strength increase with increasing amount of bonding agent. TheVulcabond TP/TEHP 50/50 mixture results were in line or even bettercompared to the neat Vulcabond TP results. Also, there was no positiveadhesion effect after storage of the adhesive composition for 24 hoursat 30° C., as expected due to the limited pot life.

Comparing the results of FIGS. 1 and 2, even though the DOTP-basedplastisols seemed to have lower initial peel strength at 2 and 3 wt %loadings of neat Vulcabond TP compared to the corresponding DINP-basedsamples; at 8 wt % of the Vulcabond TP/TEHP 50/50 mixture, the initialpeel strength surpassed that of the corresponding DINP-based plastisol.

Example 5

Besides adhesion, it is also desirable to have a more or less constantviscosity during the pot life. Increasing viscosity could have anegative effect on the penetration of the adhesive composition into thefiber structure of the fabric and reduce the final peel strength.Therefore, the viscosity of the adhesive compositions from Examples 3and 4 were monitored in the first 5 hours after addition of the bondingagent and after 24 hours.

A Brookfield viscosity measurement was conducted on the plastisols at30° C. using spindle 5, at a rotation speed of 10 rpm.

The viscosity results for adhesive compositions from Examples 3 and 4are shown in Tables 7 and 8, respectively, where TP refers to VulcabondTP and the percentages of TP are by weight.

TABLE 7 Viscosity Stability at 30° C. for DINP-Based Plastisol SamplesViscosity after n hours at 30° C. Adhesive (mPas) Formulation n = 0 n =1 n = 2 n = 3 n = 4 n = 5 n = 24 Plastisol Alone 1280 1080 1180 10001040 1000 1080 Plastisol + 2% TP 1200 1080 1040 1080 1280 1680 125000Plastisol + 3% TP 1240 1080 1160 1120 1320 1560 180000 Plastisol + 4% TP1240 1040 1160 1160 1520 1920 180000 Plastisol (duplo) 1440 1080 11201080 1120 1080 1160 Plastisol + 4% TP/ 920 800 840 880 960 1080 50000TEHP Plastisol + 6% TP/ 880 800 800 800 880 960 60000 TEHP Plastisol +8% TP/ 800 680 700 760 880 880 62000 TEHP

TABLE 8 Viscosity Stability at 30° C. for DOTP-Based Plastisol SamplesViscosity after n hours at 30° C. Adhesive (mPas) Formulation n = 0 n =1 n = 2 n = 3 n = 4 n = 5 n = 24 Plastisol Alone 1160 1000 840 880 960880 1000 Plastisol + 2% TP 1280 1560 1840 1840 2080 2040 4240Plastisol + 3% TP 1600 2000 2040 2240 2200 2440 7000 Plastisol + 4% TP1840 2440 2320 2400 2760 2800 17060 Plastisol (duplo) 1160 920 920 920880 880 880 Plastisol + 4% TP/ 960 960 960 1080 1160 1120 1600 TEHPPlastisol + 6% TP/ 840 960 1080 1120 1120 1160 2840 TEHP Plastisol + 8%TP/ 800 1120 1560 1840 1880 1960 18640 TEHP

As seen from Tables 7 and 8, the results show a stable viscosity forboth the DINP- and DOTP-based plastisols without bonding agent. Theadhesive compositions with Vulcabond TP showed higher initial viscositycompared to the samples with TP/TEHP. Overall, the Vulcabond TP samplesshowed more viscosity increase within the first 5 hours than the sampleswith TP/TEHP. TEHP provided a lower initial viscosity and betterviscosity stability.

Example 6

A bonding agent was prepared by vacuum distilling Desmodur RC (anaromatic isocyanurate trimer product from Bayer with 35 wt % ofisocyanate in ethyl acetate) to remove the majority of the ethylacetate. The ethyl acetate was replaced with TEHP. This solution wasfurther diluted with TEHP to obtain a bonding agent containing 12.5 wt %of isocyanate.

The invention has been described in detail with particular reference topreferred embodiments thereof, but it will be understood that variationsand modifications can be effected within the spirit and scope of theinvention.

We claim:
 1. A bonding composition for adhering polyvinyl chloride tofabric, comprising: (a) isocyanurate; and (b) organophosphate, whereinthe weight ratio of organophosphate to isocyanurate ranges from 4:1 to10:1.
 2. The bonding composition according to claim 1, wherein theisocyanurate comprises aromatic diisocyanate groups.
 3. The bondingcomposition according to claim 1, wherein the isocyanurate comprises2,4-toluene diisocyanate trimer.
 4. The bonding composition according toclaim 1, which comprises 8 to 20% by weight of the isocyanurate, basedon the total weight of the bonding composition.
 5. The bondingcomposition according to claim 1, wherein the organophosphate comprisesalkyl or aryl groups having 7 to 10 carbon atoms.
 6. The bondingcomposition according to claim 1, wherein the organophosphate comprisestri-ethylhexyl phosphate, tricresyl phosphate, isodecyl diphenylphosphate, 2-ethylhexyl diphenyl phosphate, or mixtures thereof.
 7. Thebonding composition according to claim 1, wherein the organophosphatecomprises tri-ethylhexyl phosphate.
 8. The bonding composition accordingto claim 1, which comprises 85 to 90% by weight of organophosphate,based on the total weight of the bonding composition.
 9. The bondingcomposition according to claim 1, wherein the weight ratio oforganophosphate to isocyanurate ranges from 7:1 to 9:1.
 10. A coatingcomposition comprising: (a) a plastisol comprising polyvinyl chloride(PVC) powder dispersed in a plasticizer comprising dioctyl terephthalateor 1,2-cyclohexane dicarboxylic acid diisononyl ester; and (b) thebonding composition according to claim
 1. 11. The coating compositionaccording to claim 10, wherein the plastisol further comprises vinylcopolymers.
 12. The coating composition according to claim 10, whichcomprises 4 to 15% by weight of the bonding composition, based on thetotal weight of the coating composition.
 13. The coating compositionaccording to claim 10, which comprises from 40 to 120 parts by weight ofplasticizer per 100 parts of PVC particles.
 14. The coating compositionaccording to claim 10, wherein the organophosphate comprisestri-ethylhexyl phosphate.
 15. The coating composition according to claim10, which further comprises flame retardants, stabilizers, fillers,pigments, chlorinated hydrocarbons, secondary plasticizers, viscositydepressants, antioxidants, UV absorbers, biocides, or mixtures thereof.16. A process for coating a fabric, comprising: (a) combining thebonding composition according to claim 1 with a plastisol comprisingpolyvinyl chloride powder dispersed in a plasticizer comprising dioctylterephthalate or 1,2-cyclohexane dicarboxylic acid diisononyl ester; and(b) coating at least one side of a fabric with the mixture from step(a).
 17. The process according to claim 16, wherein the plastisolfurther comprises vinyl copolymers.
 18. The process according to claim16, wherein the fabric comprises polyester or polyamide.
 19. The processaccording to claim 16, which further comprises (c) exposing the coatedfabric to elevated temperature to fuse the coating.
 20. An article ofmanufacture comprising a fabric coated with the coating compositionaccording to claim 10.